RESERVE.     -7'/WjS',3'.    tfS 


CONNECTICUT 

Agricultural  Experiment  Station 

NEW     HAVEN,    CONN. 
BULLETIN   195,   JULY,  1917 


ENTOMOLOGICAL  SERIES,   No.   24. 


INSECTS  INJURING  STORED  FOOD  PRODUCTS 
IN  CONNECTICUT 

By  W.   E.   BRITTON,    State  Entomologist. 


Figure  i.     Ear  of  corn  injured  by  the  European  grain  moth,  half  natural 

size. 


CONTENTS. 


Officers  and  Staff  of  Station 2 

Insects  Injuring  Stored   Food  Products 

in  Connecticut 3 

The  Grain  Beetles 3 

Common  Meal  Worm 3 

Darker  Meal  Worm 4 

Cadelle 4 

Pea  Weevil 5 

Common  Bean  Weevil  6 

Four-Spotted  Bean  Weevil 7 

Drug  Store  Beetle 7 

Confused  and  Rust-Red  Flour  Beetles.  8 

Saw-toothed  Grain  Beetle 8 

Granary  Weevil g 

Rice  Weevil g 

The  Flour  and  Meal  Moths  10 

Indian  Meal  Moth 10 


Mediterranean   Flour  Moth 

Meal  Snout  Moth 

The  Grain  Moths 

Angoumois  Grain  Moth 

European  Grain  Moth 

Other    Insects    Occasionally    Attacking 

Foods 

Control  Methods 

Temperature 

Heat 

Cold  

Air-Slaked   Lime 

Pest-proof   Packages 

Fumigation 

Carbon  Disulphide 

Hydrocyanic  Acid   Gas 

Summary  


The  Bulletins  of  this  Station  are  mailed  free  to  citizens  of  Con- 
necticut who  apply  for  them,  and  to  others  as  far  as  the  editions 
permit. 


CONNECTICUT  AGRICULTURAL  EXPERIMENT  STATION. 

OFFICERS  AND  STAFF. 


BOARD  OF  CONTROL. 
His  Excellency,  Marcus  H.  Holcomb,  ex-officio,  President. 

James  H.  Webb,  Vice  President 1  [amden 

George  A.  Hopson,  Secretary Walling  ford 

E.  H.  Jenkins,  Director  and  Treasurer New   1  taven 

Joseph  W.  Alsop \von 

Wilson  H.  Lee Orange 

Frank  H.    Stadtmueller Elmwood 

Administration.  E.   H.  Jenkins,   Ph.D.,  Director  and   Treasurer. 

Miss  V.   E.  Cole,  Librarian  and  Stenographer. 
Miss   L.   M.   Brautleciit,  Bookkeeper  and  Stenographer. 
William   Veitcii,   In  charge  of  Buildings  and   Grounds. 

Chemistry. 

Analytical    Laboratory. John  Phillips  Street,   M.S.,   Chemist   in   Charge. 
E.  Monroe  Bailey,  Ph.D.,  j 

C.   B.   Morison,   B.S.,  C.   E.   Shepherd,      Assistants. 

W.  L.  Adams,  B  S. 

Hugo  I-ange,  Laboratory  Helper. 

V.   L.   Churchill,  Sampling  Agent. 

Proteid    Research.  T.   B.   Osborne,   Ph.D.,   D.Sc,   Chemist   in   Charge. 

Miss   E.    L.   Ferry,   M.S.,   Assistant. 

Botany.  G.  P.  Clinton,   Sc.D.,  Botanist. 

E.   M.   Stoddard,   B.S.,  Assistant  Botanist. 
Florence  A.  McCormick,   Ph.D.,  Scientific  Assistant 
G.   E.   Graham,   General  Assistant. 

Entomology.  W.    E.    Britton,   Ph.D.,    Entomologist;    State   Entonv  I 

B.  H.  Walden,   B.Agr.,  First  Assistant. 

Q.   S.    Lowry,   B.Sc,   1.   W.    Davis.    B.Sc,  I     , 

n,r    t>    t  t>  o  ,  Assistants. 

M.  P.  Zappe,  B.S..  » 

Miss  G.  A.  Foote,   B.A.,  Stenographer. 

Forestry.  Walter   O.   Filley,    Forester;    also   Stale   Forester 

and  Stale  l-'fics!   Fire   Warden. 
A.    K.    Moss,    M.F.,  Assistant  State  and  Station   Forester. 
M  iss    E.    I ,.   A\  im  .   $  tenogt  apher. 

Plant    Breeding.  Donald   F.  Jones,   M.S..  Plant  Breeder. 

C.  D.    Hubbell,   Assistant. 

Vegetable    Growing.  . 


Insects  Injuring  Stored  Food  Products  in  Connecticut. 

By  W.  E.  Britton,  State  Entomologist. 


The  importance  of  growing  more  food  for  the  people  of  this 
country  cannot  be  over-emphasized,  and  the  various  efforts  along 
this  line  and  the  publications  giving  information  regarding 
methods  are  all  praiseworthy.  Nevertheless,  it  is  perhaps  equally 
important  to  conserve  the  food  supplies  already  grown  and 
stored.  It  has  been  estimated  that  insects  take  an  annual  toll 
of  about  five  per  cent  of  the  value  of  the  stored  food  products, 
amounting  to  $200,000,000.00  each  year,  in  the  United  States. 
Most  of  this  loss  is  wholly  preventable  if  attention  is  given  the 
matter  at  the  right  time,  and  there  is  no  time  when  control 
methods  can  be  enforced  with  greater  profit  to  the  owner,  or  with 
greater  benefit  to  our  country  and  to  mankind  than  the  present. 

The  object  of  this  bulletin  is  to  place  before  the  people  of 
Connecticut  a  brief  account  of  the  principal  insects  attacking  and 
injuring  stored  grains  and  food  products  in  the  state,  and  to 
suggest  methods  of  controlling  them.  The  figures  are  included 
for  the  purpose  of  illustrating  the  text  and  of  giving  an  idea 
of  the  general  appearance  of  the  insects. 

These  insects  belong  in  two  large  natural  groups :  the  Beetles 
(Coleoptera)  and  the  Moths  (Lepidoptera).  The  principal  fea- 
tures of  each  are  given  to  enable  the  reader  to  identify  the 
species,  but  as  control  measures  are  similar  for  all,  information 
on  this  point  is  given  in  a  separate  chapter  on  page  16  of  this 
bulletin. 

THE  GRAIN  BEETLES. 

The  Common  Meal  Worm,  Tenebrio  molitor  Linn. 

In  and  around  the  bottoms  of  bins  and  barrels  where  corn  meal, 

flour,  or  other  cereals  are  stored,  one  often  finds  yellow  larvae 

about  an  inch  in  length  and  resembling  wire  worms.     These  feed 

upon  the  meal  and  are  called  meal  worms. 

The  adult  is  a  shining,  black  or  dark  brown,  beetle,  somewhat 
more  than  half  an  inch  in  length,  with  thorax  rather  finely  punc- 
tured and  wing-covers  longitudinally  striated  or  grooved.     The 


4  CONNECTICUT    EXPERIMENT    STATION    BULLETIN     [95. 

beetle  lays  its  white  eggs  in  the  meal,  usually  in  masses,  with  a 
juice  or  sticky  material  which  causes  the  meal  to  adhere  to  the 
eggs.  The  eggs  hatch  in  about  two  weeks  and  the  larvae  feed 
upon  the  meal  for  three  months  or  longer  before  pupating.  The 
pupal  stage  requires  about  two  weeks,  and  normally  there  seems 


Figure  2.     Common  meal  worm,  adult  and  larva,  natural   <ize. 

to  be  but  one  generation  each  year.  The  adults  mostly  emerge 
in  the  spring,  but  where  the  meal  is  stored  in  the  house,  or  in  a 
heated  building,  they  may  appear  at  any  time  of  the  year.  This 
insect  is  shown  in  figure  2. 

The  Darker  Meal  Worm,  Tenebrio  obscurus  Fabr. 

This  insect  is  much  like  the  preceding  except  that  the  larvae 
are  darker  in  color  and  the  adult  beetles  are  dull  instead  of  shiny. 
The  life  history  and  injuries  are  similar  and  both  often  occur  in 
the  same  place. 

The  treatment  is  also  the  same  for  both  species,  viz. ;  fumi- 
gating with  carbon  disulphide  or  heating  the  meal  in  an  men  for 
a  short  time. 

The  Cadelle,  Tenebrioides  mauritanicus  Linn. 

The  larva  of  this  beetle  is  dirty-white,  with  head,  prothorax 
and  tip  of  abdomen  dark  brown,  and  when  fully  grown  it  meas- 
ures about  three-fourths  of  an  inch  in  length.  It  ha-  the  habit 
of  tunneling  into  wood  to  make  its  cocoon,  at  least  when  sofl 
pine  is  available!  The  pupa  stage  evidently  lasts  three  or  four 
weeks. 

The  adult  beetle  is  brown  ami  shiny,  and  about  three-eighths  of 
an  inch  long.  It  lays  while  eggs  which  are  ;i  trifle  over  a  milli- 
meter Ion"  and  one-fourth  as  thick. 


THE    PEA    WEEVIL. 


5 


There  is  a  single  generation  annually,  and  the  cadelle  feeds  on 
various  kinds  of  stored  foods  and  plant  products  and  is  also 
partially  predaceous,  as  Chittenden*  states  that  both  larvae  and 
adults  attack  and  destroy  other  grain  insects  which  they 
encounter.     Nevertheless,  the  cadelle  is  capable  of  causing  con- 


Figure  3.     Cadelle,  adult  and  larva,  twice  natural  size. 


siderable  injury  and  the  treatment  is  the  same  as  for  the  other 
meal  worms.  The  larvae  of  the  cadelle  have  been  reported  from 
many  unexpected  places,  such  as  in  sugar,  in  bottles  of  milk, 
in  powdered  hellebore,  and  boring  through  the  parchment  paper 
of  jars  of  jams  and  jellies.  In  some  of  these  places  they 
probably  occurred  accidentally.  Larva  and  adult  are  shown  in 
figure  3. 

The  Pea  Weevil,  Bruchus  pisorum  Linn. 
The  adult  beetle  is  about  one-fifth  of  an  inch  long,  and  the 
wing  covers  are  marked  with  small  black  and  white  spots.  It 
lays  eggs  singly  on  the  outside  of  the  green  pods  in  the  field, 
and  the  larva  tunnels  through  the  pods  and  into  one  of  the  green 
peas.  The  insect  does  not  mature  until  the  peas  have  ripened 
and  have  been  harvested  and  placed  in  storage.  Then  it  is  com- 
mon to  find  a  single  round  hole  in  a  pea  where  the  adult  has 
emerged.  Sometimes  nearly  every  pea  has  a  hole  in  it,  and 
many  larvae  are  unquestionably  cooked  and  eaten  in  green  peas ; 


*  F.    H.    Chittenden,    Farmer's    Bulletin    No.   45,    U.    S.    Department   of 
Agriculture,  page  19,  1896. 


6  CONNECTICUT    EXPERIMENT    STATION    BULLETIN     1 95. 

but  the  insect  does  not  g'o  on  breeding"  in  dry  stored  peas,  there 
being-  only  one  brood  each  year. 

The  pea  weevil  is  more  serious  in  the  .Middle  Atlantic  than  in 
the  Northern  States,  but  it  is  present  in  Connecticut.  In  the 
Southern  States  it  is  claimed  that  late  planting  brings  compara- 


Figure  4.     Pea  weevil,  adult  beetle,   four  times  enlarged. 

tive  immunity  from  attack  but  in  the  writer's  experience  late 
planted  peas  seldom  produce  a  satisfactory  crop  here.  Hence  it 
is  better  to  treat  the  seed  soon  after  harvesting,  and  to  make 
allowance  in  planting  for  a  certain  percentage  of  injured  seed. 
This  insect  is  shown  in  figure  4. 

The  Common  Bean  Weevil,  Bruchus  obtectus  Say. 
This  is  probably  the  greatest  enemy  of  beans  in  Connecticut. 
and  though  in  size  somewhat  smaller  than  the  pea   weevil  and 


Figure  5.  Common  bean  wee- 
vil. Adult  beetles,  four  times 
enlarged. 


Figure  6.  Infested  cow  pea-. 
showing  eggs  and  exil  holes  oi 
bean   weevil,  natural  size. 


THE    DRUG    STORE    BEETLE.  7 

resembling  it  in  color  and  markings,  it  differs  from  it  by  con- 
tinuing to  breed  in  the  dry,  stored  seed.  There  are  six  genera- 
tions annually  in  the  District  of  Columbia,  and  a  smaller  number 
in  the  northern  states.  Stored  beans  are  often  entirely  destroyed, 
or  at  least  rendered  unfit  for  planting,  or  as  food  for  man  or 
beast.  The  beans  often  have  several  holes  in  each  where  the 
adults  have  emerged,  and  as  many  as  28  have  been  found  in  a 
single  seed.  Severely  weeviled  beans  are  almost  useless  for 
planting,  but  the  good  seed  may  be  separated  from  the  infested 
seed  by  throwing  into  water.  The  injured  seed  will  float  and 
may  be  discarded.  This  beetle  and  its  work  are  shown  in 
figures  5  and  6. 

The    Four-Spotted    Bean    Weevil,    Britclius   quadrimaculatus 

Fabr. 
This  species  is  somewhat  more  slender  than  the  preceding  and 
has  different  markings.     Its  habits  and  life  history  are  similar 
and  the  same  control  methods  may  be  practiced. 

The  Drug  Store  Beetle,  Sitodrepa  panic ea  Linn. 

Of  all  the  insects  attacking  stored  food  products,  perhaps  none 
is  more  cosmopolitan  or  feeds  upon  a  greater  number  of  different 
kinds  than  the  drug  store  beetle.  It  is  a  common  pest  of  all 
kinds  of  stored  vegetable  foods  and  may  be  found  in  breakfast 


Figure  7.     Drug  store  beetle.     Adults,   four   times   enlarged. 


foods,  or  the  dried  roots,  stems,  bark,  and  seed  capsules  com- 
monly called  spices.  It  feeds  also  on  the  parts  of  plants  used  as 
drugs,  often  eating  those  which  are  bitter  and  poisonous  to  man, 
It  has  been  recorded  as  attacking  forty-five  different  drugs.  It 
is  now  distributed  throughout  the  civilized  world,  and  four  or 


8 


CONNECTICUT    EXPERIMENT    STATION    BULLETIN    1 95. 


five   generations    may   occur    in    a    year,    especially    in    a    heated 
building. 

The  beetle  is  about  one-tenth  of  an  inch  in  length,  covered 
with  a  silky  pubescence,  and  reddish-brown  in  color.  The  wing- 
covers  are  longitudinally  striated  and  the  antennae  terminate  in 
three  long  segments  forming  the  so-called  "club."  The  larvae 
are  white,  with  dark  mouth  parts,  and  assume  a  curved  attitude 
when  at  work  in  their  burrows.     The  adult  is  shown  in  figure  7. 

The  Confused  Flour  Beetle,  Tribolium  confusum   Duv.  and 
The  Rust-red  Flour  Beetle,  Tribolium  ferrugineum  Fabr. 

The  confused  flour  beetle  has  been  known  to  occur  in  this 
country  for  nearly  twenty-five  years  and  has  caused  injury 
throughout  the  land.  It  attacks  seeds,  stored  cereals  and  other 
starchy  foods  and  drugs,  and  is  a  pest  in  flour  and  grain  mills. 

The  adult  is  a  flattened  brown  beetle,  less  than  a  sixth  of  an 
inch  in  length.  There  may  be  as  many  as  four  generations 
annually  in  a  heated  storehouse. 

The  rust  red  flour  beetle  closely  resembles  the  preceding,  but 
is  not  nearly  as  common  in  Connecticut.  It  is  a  pest  in  the 
Southern  States  and  is  often  shipped  north  in  rice  or  other 
starchy  food  products. 

The  Saw-toothed  Grain  Beetle,  Silvanus  surinamensis  Linn. 

One  of  the  most  common  beetles  in  grain  and  stored  food 
products  is  the  saw-toothed  grain  beetle.  It  is  less  than  an* eighth 
of  an  inch  lon°\  flattened,   sfrooved  longitudinally,   with   teeth- 


Figure  8.     Saw-toothed  grain  beetle   Eour  times  enlarged. 


like  projections  on  tin-  sides  oi  the  thorax,  ami  brown  in  color. 
The  larva  is  white,  extremely  active,  and  makes  its  pupa  case  on 
some  convenient  surface  by  joining  together  panicles  oi  the 
infested  material  with  some  adhesive  substance  which  it  secretes. 


THE    GRANARY    WEEVIL.  9 

There  are  probably  four  or  five  generations  each  year,  and  the 
beetles  eat  through  paper  bags  and  pasteboard  boxes  to  reach 
foodstuffs  inside.  Though  perhaps  preferring  farinaceous 
foods,  this  beetle  often  infests  fruits  and  almost  all  kinds  of 
stored  food  products.  This  beetle  and  its  injury  to  corn  are 
shown  in  figures  8  and  9. 


Figure    9.      Peruvian    seed    corn    injured    by    saw-toothed    grain    beetle, 

reduced  one-half. 

A  flat,  smooth,  reddish-brown  beetle,  still  smaller  than  the  pre- 
ceding, is  occasionally  found  infesting  wheat  bran  or  other 
cereals.  This  is  Lcemophlceus  pusillus  Schr.,  one  of  the  minor 
pests  but  nevertheless  capable  of  causing  much  injury. 

The  Granary  Weevil,  Calandra  granaria  Linn. 
Both  this  weevil  and  the  following  belong  to  the  family  Calan- 
dridae  or  snout  beetles.  The  adult  is  a  shiny  reddish-brown 
snout  beetle  nearly  an  eighth  of  an  inch  in  length,  with  a  long 
proboscis.  The  larva  is  a  legless  grub.  Both  adult  and  larva 
feed  upon  the  kernels  of  the  grain.  There  are  four  or  five 
generations  each  year  in  the  vicinity  of  Washington,  D.  C,  and 
more  farther  south.  It  attacks  and  injures  maize  and  all  of  the 
small  grains. 


The  Rice  Weevil,  Calandra  orysae  Linn. 

This   species   resembles   the   preceding   except   that   it   is   dull 

brown  instead  of  shining,  and  the  thorax  is  more  densely  pitted. 

There  are  four  more  or  less  distinct  red  spots  on  the  wing-covers. 

This  insect  is  often  found  in  the  field  and  takes  its  name  from 


TO  CONNECTICUT    EXPERIMENT    STATION    BULLETIN     1 95. 

the  rice  which  it  infests.     Its  habits  and  life  history  are  otherwise 
similar  to  the  preceding.     It  is  shown  in  figure  10. 


Figure  10.     Rice  weevil.     Adults  four  times  enlarged. 

THE  FLOUR  AND  MEAL  MOTHS. 
The  Indian  Meal  Moth,  Ploclia  interpunctella  Hubn. 
Considerable  damage  is  done  each  year  in  mills,  granaries,  seed 
warehouses,  etc.,  by  the  Indian  meal  moth,  which  is  also  a  com- 
mon  pest   of   the   household,   as   it   attacks   nearly   all   kinds   of 


FIGURE   ii.     Kernels   uf  corn   injured   by  the   Indian   meal   moth.     Natural 

size. 


THE    MEDITERRANEAN    FLOUR    MOTH.  H 

vegetable  food  products.  Each  year  some  food  material  infested 
by  this  insect  is  brought  to  the  writer's  attention.  In  1905  some 
large  seed  warehouses  near  New  Haven  were  found  infested, 
and  one  room  was  fumigated  with  hydrocyanic  acid  gas.  This 
treatment  killed  the  larvae  crawling  about,  and  those  at  work 
near  the  outside  of  the  bags,  and  at  first  seemed  to  be  effective. 
Later,  however,  living  larvae  appeared  from  inside,  showing  that 
the  gas  did  not  penetrate  far  into  the  mass  of  grain. 

The  larvae  web  together  the  grain  and  flour,  especially  around 
the  outside.  One  100-pound  bag  of  corn  was  emptied  and  seven 
pounds  adhered  to  the  bag.  The  kernels  were  eaten  at  the 
embryo,  and  are  shown  in  figure  11. 

The  eggs  are  small,  white,  and  laid  singly  or  in  groups,  and 
each  female  may  lay  as  many  as  350.  The  larva  is  whitish,  and 
spins  a  silk  thread  wherever  it  feeds  and  travels,  and  the  web 


Figure  12.  Indian  meal  moth,  a,  adult;  b,  pupa;  c,  larva,  side  view; 
d,  head  of  larva,  front  view;  e,  first  abdominal  segment  of  larva;  f, 
larva,  dorsal  view — all  greatly  enlarged.  (After  Chittenden,  Bur.  of  Ent., 
U.  S.  Dept.  of  Agriculture.) 

holds  together  the  particles  of  food  material.  Pupation  takes 
place  in  a  silken  cocoon-like  web  from  which  the  moths  emerge. 
From  four  to  five  weeks  only  are  required  for  a  generation  to 
develop.  In  a  heated  building  this  insect  will  breed  throughout 
the  year. 

The  adult  is  a  small  moth  having  a  wing-spread  of  about  five- 
eighths  of  an  inch;  forewings  whitish  at  base  with  distal  half 
reddish-brown,  as  shown  in  figure  12. 


The  Mediterranean   Flour   Moth,  Ephestia   kuehniella  Zell. 

This  insect  is  regarded  by  Chittenden  as  the  most  important 

of  all  the  species  infesting  flour  and  grain  mills.      It  has  been 


12  CONNECTICUT    EXPERIMENT    STATION    BULLETIN    195. 

reared  from  flour  in  New  Haven  and  has  been  taken  at  Bran  ford. 
In  life  history  and  injury  the  Mediterranean  flour  moth  resembles 
the  Indian  meal  moth,  and  in  heated  buildings  five  or  six  broods 
mav  occur  each  vear.     The  moth  is  shown  in  figure   1  ^.     It  is 


Figure  13.     Mediterranean  flour  moth  and  cocoons,  slightly  enlarged. 

larger  than  the  Indian  meal  moth  and  has  a  wing-spread  of  about 
an  inch.  The  forewings  are  dull  lead-gray,  crossed  by  zigzag 
darker  lines  or  bands.  Not  only  does  this  insect  injure  flour  and 
grain  but  also  feeds  upon  almost  any  kind  of  stored  vegetable 
food  products. 

The  Meal  Snout  Moth,  PyraMs  farinalis  Linn. 

This  insect  infests  flour,  meal,  and  other  stored  food  products, 
though  not  as  serious  a  pest  as  the  Indian  meal  moth  or  the 
Mediterranean  flour  moth. 

The  larvae  have  the  habit  of  constructing  long  tubes  by  bind- 
ing together  with  silk  small  particles  of  the  meal  or  food  material. 
In  these  tubes  the  larvae  live  and  hide  until  fullv  grown  when 


Figure  14.     Meal  snout  moth.     Natural  size. 


they  leave  the  tubes  and  spin  their  cocoons,  usually  in  or  just 
outside  of  the  infested  material.  There  are  probably  three  or 
four  generations  each  year,  though  further  studies  are  needed  in 
this  latitude  to  determine  this  point. 


THE    ANGOUMOIS    GRAIN    MOTH. 


13 


The  adult  has  a  wing-spread  of  about  an  inch,  is  light  brown, 
with  thorax,  base  and  apex  of  fore  wings  darker  brown,  and  with 
whitish  wavy  lines  crossing  front  and  rear  wings,  as  shown  in 
figure   14. 

THE  GRAIN  MOTHS. 
The  Angoumois  Grain  Moth,  Sitotroga  cerealella  Oliv. 
This  destructive  insect  was  known  in  France  nearly  two  hun- 
dred years  ago,  and  was  somehow  brought  to  this  country  in 
the  early  colonial  days,  and  became  established  in  North  Carolina 
and  Virginia.  Since  then  it  has  spread  northward  to  Massa- 
chusetts, New  York  and  Michigan  and  throughout  the  southern 
states,  where  it  does  much  damage.  The  writer  first  noticed  it 
in  Connecticut  nearly  twenty  years  ago,  and  has  run  across  it  a 
number  of  times  since.  It  is  primarily  a  pest  of  stored  grains, 
especially  corn  on  the  ear,  which  if  infested  soon  appears  as  in 


Figure  15.     Pop  corn  showing  exit  holes  of  Angoumois  grain  moth. 

Natural  size. 


figure  15.  The  emerging  moths  leave  small  circular  holes  in  the 
kernels.  Infested  grain  is  injured  not  only  for  seed,  but  also 
for  feeding  purposes ;  as  it  has  been  estimated  that  it  loses  within 
six  months  40  per  cent  of  its  weight  and  75  per  cent  of  the 
starchy  matter.  The  moth  lays  whitish  eggs  on  the  kernels  of 
corn,  and  they  soon  turn  to  a  pale  reddish  color  and  hatch  in 
five  or  six  days.  Two  or  more  larvae  may  occupy  a  single  kernel 
of  maize,  though  only  one  occurs  in  a  grain  of  wheat.  The 
adult  is  a  light,  grayish-brown  moth,  having  a  wing-expanse  of 
about  half  an  inch,  somewhat  resembling  a  clothes  moth.  Out 
of  doors  in  the  southern  states  there  are  at  least  four  broods 


*4 


CONNECTICUT    EXPERIMENT    STATION    BULLETIN    1 95. 


annually  and  the  larva  passes  the  winter  in  kernels  of  grain.  In 
this  climate  it  breeds  only  in  stored  grain,  and  in  heated  buildings 
this  goes  on  continuously,  there  probably  being  five  or  six  genera- 
tions, depending  upon  the  temperature. 

The  European  Grain  Moth,  Tinea  granella  Linn. 

Compared  with  the  Angoumois  grain  moth  this  moth  is  of 
secondary  importance,  and  seems  to  be  not  especially  destructive 
in  the  United  States.  It  infests  all  kinds  of  cereals,  and  as  each 
larva  may  pass  from  one  kernel  into  another,  webbing  them 
together  until  twenty  or  thirty  grains  are  spoiled,  it  is  apparent 
that  considerable  injury  must  result. 


Figure  16.     European  grain  moth.     Three  times  enlarged. 

This  moth  was  first  found  in  Connecticut,  in  1006.*  in  a  seed 
warehouse  in  Milford.  It  is  now  distributed  throughout  the 
northern  states. 

The  adult  is  a  slender  moth  with  a  wing-spread  of  half  an 
inch,  creamy  white  mottled  with  brown,  and  is  shown  in  figure 
16.     Its  work  is  shown  in  figure  1. 


OTHER  INSECTS  OCCASIONALLY  ATTACKING 
FOODS. 

The  large  cabinet  beetle,  Trogoderma  tarsals  Melsh.,  fre- 
quently injuries  seeds  and  is  shown  in  figure  17.  The  small 
cabinet  beetle,  Anthrenus  verbasci  Linn.,  and  the  black  carpel 
beetle,  Attagenus  picens  Oliv.,  occasionally  attack  and  injure 
food  products,  though  the  latter  is  a  more  important  pesl  of 
clothingr. 


*  Report  of  this  Station   l~<>r   190(1,  page  305. 


OTHER    INSECTS    INJURING    FOODS. 


IS 


The  larder  or  bacon  beetle,  Dermestes  lardarius  Linn.,  the  red- 
legged  ham  beetle,  Necrobia  rufipes  Fabr.,  and  certain  species 
of  mites  of  the  genus  Tyroglyphits  sometimes  injure  dried  meats, 
cheese,  dried  fruits,  cereals,  etc.  The  cigarette  beetle,  Lasio- 
derma  serricorne  Fabr.,  though  primarily  a  pest  of  tobacco,  feeds 


Figure  17.     Seeds  injured  by  the  large  cabinet  beetle.     Natural  size. 


upon  the  spices,  rice,  figs  and  many  other  food  products.  Then 
the  cheese  skipper,  Piophila  casei  Linn.,  which  occurs  every- 
where, often  attacks  cheese  and  the  larvae  may  be  found  tun- 
neling in  it.  Cheese  should  be  kept  covered  and  should  be 
examined  every  day  in  warm  weather.  Hams  and  other  kinds 
of  meat  are  infested  only  in  certain  portions  which  can  be  cut 
off  and  the  remainder  used  for  food. 

A  species  of  book-lice,  Troctes  divinatorius  Mull,  (order  Cor- 
rodentia),  was  found  eating  corn  at  the  Station  in  1900.  The 
sample  was  stored  in  a  ground  glass-stoppered  jar.  The  outer 
surface  of  the  kernels  was  wholly  eaten  off,  so  as  to  render  the 
variety  wholly  unrecognizable. 

Cockroaches  and  ants  are  also  frequently  injurious  in  pantries 
and  storehouses.  The  former  are  usually  susceptible  to  the 
influence  of  powdered  borax,  and  ants  can  usually  be  driven  away 
by  scattering  naphthalene  flakes  about  on  the  floor  and  shelves, 
especially  where  the  ants  have  their  runways. 

The  other  insects  mentioned  in  this  chapter  without  control 
methods  may  be  killed  by  heat  or  by  fumigation. 


l6  CONNECTICUT    EXPERIMENT    STATION    BULLETIN     I95. 

CONTROL  METHODS. 

The  chief  methods  for  preventing  damage  by  the  insects  men- 
tioned in  the  foregoing  pages  are :  the  use  of  high  and  low- 
temperature,  air-slaked  lime,  pest  proof  packages  and  fumigation. 

Temperature. 
Temperature   is   recognized  as  an  important   factor  in   insect 
development,  and  often  determines  in  a  measure  the  number  of 
annual  generations  of  certain  species.     Extremes  in  temperature 
are  sometimes  employed  for  the  control  of  insects. 

heat. 

It  has  long  been  known  that  heat  will  kill  insects,  and  one  of 
the  simplest  methods  of  destroying  them  in  small  packages  of 
flour  or  other  food  products  is  to  heat  it  in  the  oven  for  an  hour 
or  so.  Following  this  idea  Professor  George  A.  Dean  started 
some  experiments  in  Kansas  in  1910  to  determine  the  fatal  high 
temperatures  for  certain  grain-infesting  insects,  and  found  that 
few  insects  can  withstand  a  temperature  of  from  Ii8°-I25°  F. 
for  any  length  of  time.  In  a  mill  there  are  accumulations  of 
meal  and  flour  on  the  floor,  beams,  machinery,  and  in  the  corners 
everywhere  in  which  insects  can  breed.  To  keep  a  mill  free 
from  this  accumulation  and  absolutely  clean  is  almost  an  impos- 
sibility. By  the  use  of  heat,  however,  the  insects  can  be  killed 
from  time  to  time  without  serious  inconvenience,  without  shut- 
ting down  the  mill,  and  without  great  expense.  It  requires  extra 
steam  pipes  sufficient  to  raise  the  temperature  to  about  120°  F., 
and  to  keep  it  there  for  a  period  of  five  or  six  hours  to  allow  the 
heat  to  penetrate  the  bins  and  bags  of  grain.  Professor  Dean  has 
published  three  papers  on  this  subject,*  and  any  one  interested 
should  write  to  him  for  further  advice. 

Any  grain  or  seeds  which  are  intended  for  planting  should  not 
be  heated  to  a  point  much  greater  than  1300  F.  as  there  is  danger 
of  injuring  the  vitality,  which  with  some  seeds  ceases  if  the 
temperature  approaches  1500  F. 

Any  product  to  be  used  for  food  will  not  be  injured  by  this 

*  Journal  of  Economic  Entomology.  Vol.  IV.  page  14-'.  191 1;  Vol.  VI. 
page  40.  1913.  Kansas  Agricultural  Experiment  Station,  Bull.  189.  July. 
I9I3- 


CONTROL    METHODS. 


n 


heating  method  and  even  the  eggs  and  larvae,  as  well  as  the  adult 
insects,  are  killed  by  it. 

COLD. 

A  low  temperature  is  not  so  frequently  used  for  destroying 
insects,  yet  it  has  been  known  for  a  long  time  that  insect  develop- 
ment is  arrested  or  suspended  altogether  in  cold  storage. 

Mr.  J.  A.  Manter*  of  Storrs,  Conn.,  states  that  the  bean 
weevil  will  not  breed  in  cold  storage  and  suggests  that  beans  be 
stored  in  unheated  buildings.  This  idea  may  be  carried  out  in 
practice  with  certain  other  stored  food  insects  but  the  exact 
temperatures  have  not  yet  been  determined  for  all  species. 

Air  Slaked  Lime. 
A   very   simple   and   promising   treatment    to    prevent    weevil 
injury  to  peas,  beans,  cow  peas  and  possibly  to  other  kinds  of 


Figure  18.  Effect  of  air  slaked  lime.  Treated  seeds  at  right.  (After 
Metcalf,  North  Carolina  Agricultural  Experiment  Station.  Jour.  Econ. 
Ent.,  Vol.  10,  plate  3,  fig.  2.) 


Journal  of  Economic  Entomology,  Vol.  X,  page  193,  1917. 


l8  CONNECTICUT    EXPERIMENT    STATION    BULLETIN     195. 

seeds  has  recently  been  discovered  by  Mr.  X.  P.  Metcalf*  of 
the  North  Carolina  Station.  This  consists  of  applying  air-slaked 
lime  to  the  seeds,  using  one  part  by  weight  of  lime  to  two  parts 
of  seeds  when  placing  the  crop  in  storage.  For  small  quantities, 
say  less  than  a  half  peck,  Professor  Metcalf  advises  the  writer 
in  a  letter  that  four  parts  of  lime  should  be  used  to  one  part  of 
seeds ;  for  quantities  between  a  half  peck  and  three  bushels,  use 
equal  amounts  of  lime  and  seeds.  The  quantity  of  seeds  to  be 
stored  thus  influences  the  effectiveness  of  the  treatment  and 
•necessitates  greater  proportions  of  lime  for  small  quantities.  In 
time  this  method  may  be  found  applicable  to  other  kinds  of  seeds 
and  against  other  insects.  It  has  the  advantage  of  being  harm- 
less to  seeds  and  to  the  operator,  as  well  as  being  convenient  to 
procure  and  relatively  inexpensive.  Professor  Metcalf  is  now- 
completing  further  tests  of  this  material.  Figure  18  shows 
untreated  seeds  and  those  treated  with  lime. 

Pest-proof  Packages. 

Materials  sealed  in  glass  or  metal  containers  are  usually  safe 
against  insects  as  long  as  they  remain  unopened.  We  have  a 
number  of  records  showing  that  the  smaller  beetles,  like  the  saw- 
toothed  grain  beetle,  will  enter  poorly  stoppered  glass  bottles  and 
jars  and  even  tin-stoppered  cans.  The  material  is  of  course 
often  infested  before  placing  in  the  containers. 

Mr.  William  B.  Parker  of  the  U.  S.  Bureau  of  Entomology 
has  made  investigations  and  suggestsf  a  sealed  paper  carton,  for 
packing  cereals  which  are  to  be  placed  upon  the  market.  While 
this  may  prevent  infestation  in  stores  and  warehouses,  in  the 
household  many  opened  packages  often  attract  insects,  and  if 
stored  for  a  long  time  no  paper  package  is  insect-proof.  Hence 
other  methods  must  be  resorted  to,  especially  in  dwelling  houses, 
to  keep  the  foodstuffs  free  from  insect  attack. 

FuM  [GATI0N. 
Fumigation  has  long  been  practiced  to  kill  insects  in  seeds  and 
food  substances.     For  this  purpose  two  materials  are  commonly 
used,  viz.,  carbon  disulphide  and  hydrocyanic  acid  gas, 

*  Journal  of   Economic   Entomology,   Vol.  X.  page  74,   1017. 
f  Bulletin   15,  U.  S.   Department  of  Agriculture,   1913. 


CONTROL    METHODS.  I  9 

CARBON    BISULPHIDE    (BISULPHIDE) . 

This  is  a  colorless,  ill-odored  liquid  which  volatilizes  at  air 
temperatures,  more  readily  in  warm  weather,  and  the  fumes  are 
deadly  to  all  forms  of  insect  life.  Carbon  disulphide  may  be 
purchased  in  pound  bottles  from  any  wholesale  druggist,  and  as 
it  is  inflammable  when  the  fumes  are  mixed  with  air,  it  should 
not  be  used  by  any  one  smoking,  or  at  night  with  oil  or  gas  lights 
near.  As  the  fumes  are  heavier  than  air  the  liquid  should  be 
placed  on  top,  rather  than  at  the  bottom  of  the  grain,  seeds  or 
material  to  be  treated.  It  should  also  be  placed  in  a  shallow  dish 
to  facilitate  volatilization.  The  quantities  used  are  about  one 
pound  to  each  40  bushels  of  seeds,  or  to  each  100  cubic  feet  of 
space.  In  a  tight  barrel  containing  grain  or  seeds,  about  one- 
half  cupful  of  the  liquid  should  be  placed  in  a  saucer  on  top  of 
the  seeds,  the  barrel  covered  tightly  and  allowed  to  remain  all 
day  or  longer.  For  smaller  receptacles,  use  proportionate  quan- 
tities of  the  liquid.  Carbon  disulphide  is  more  convenient,  less 
dangerous  to  the  operator,  and  its  fumes  penetrate  better  than 
hydrocyanic  acid  gas.  A  recent  bulletin  by  Dr.  Hinds*  contains 
much  information  about  carbon  disulphide  and  may  be  obtained 
by  applying  to  the  U.  S.  Department  of  Agriculture, 
Washington,  D.  C. 

HYDROCYANIC    ACID    GAS. 

This  is  a  deadly  poisonous  gas  generated  by  putting  together 
cyanide,  sulphuric  acid  and  water.  Potassium  cyanide  was  for- 
merly recommended,  but  sodium  cyanide  is  now  the  cyanide  of 
commerce  and  is  effective.  The  quantities  for  100  cubic  feet  of 
space  are  as  follows : — 

Sodium    cyanide    1  oz. 

Commercial  sulphuric  acid    2  fluid  ozs. 

Water    4      " 

If  a  room  is  to  be  fumigated  its  cubic  space  must  be  ascer- 
tained and  the  chemicals  carefully  weighed  or  measured.  It 
must  be  made  reasonably  tight,  and  provision  must  be  made  for 
opening  from  the  outside  at  least  one  window  or  door,  besides  the 
exit.     The  generating  jar  may  be  earthen  or  stoneware  but  never 


*  Farmers'  Bulletin  799,  U.   S.   Department  of  Agriculture,   June,   1917. 


20  CONNECTICUT    EXPERIMENT    STATION    BULLETIN     I  95. 

metal.  The  acid  may  be  diluted  with  the  water,  the  cyanide 
placed  in  a  paper  or  cheesecloth  bag,  and  when  all  is  ready  the 
operator  should  drop  the  bag  into  the  jar  and  with  bated  breath 
retire  at  once  and  close  and  lock  the  door.  One  full  inhalation 
of  this  gas  will  drop  a  man,  and  no  carelessness  should  be  per- 
mitted. The  house  or  room  should  be  exposed  for  at  least  two 
hours  and  may  remain  closed  over  night  or  over  Sunday.  The 
fumes  do  not  penetrate  as  well  as  those  of  carbon  disulphide. 

Recently  Mr.  E.  R.  Sasscer  of  the  U.  S.  Department  of  Agri- 
culture has  devised  an  apparatus  for  fumigating  cotton  bales, 
bags  of  seeds,  etc.  By  removing  the  air  and  forcing  the  gas 
into  a  partial  vacuum  thus  created,  most  insects  are  killed  with 
a  half  hour  exposure.*  On  account  of  the  danger,  trouble  of 
generating,  etc.,  the  average  farmer  and  householder  will  seldom 
use  hydrocyanic  acid  gas  and  will  find  carbon  disulphide  or  heat 
sufficient  to  meet  his  needs. 


SUMMARY. 

Much  damage  results  each  year  in  Connecticut  to  cereals 
and  other  stored  food  products  from  the  attacks  of  insects. 
This  injury  has  been  estimated  at  five  per  cent  of  the  total 
value  of  the  products,  or  $200,000,000.00  each  year  for  the 
United  States,  and  is  wholly  preventable. 

The  insects  are  chiefly  beetles  (Coleoptera)  and  moths 
(Lepidoptera).  The  former  include  the  meal  worms,  cadelle. 
pea  and  bean  weevils,  drug  store  beetle,  confused  flour  beetle, 
rust-red  flour  beetle,  saw-toothed  grain  beetle,  granary  weevil, 
rice  weevil,  large  and  small  cabinet  beetles,  black  carpet  beetle, 
larder  beetle,  red-legged  ham  beetle,  and  cigarette  beetle. 
The  latter  include  the  Indian  meal  moth,  Mediterranean  flour 
moth,  meal  snout  moth,  Angoumois  grain  moth,  and  European 
grain  moth.  Other  insects  like  the  cheese  skipper  (a  fly),  a 
book  louse,  ants,  cockroaches,  and  even  mites  occasionally 
cause  damage. 

The  most  important  of  these  pests  are  described  briefly  in 
the  preceding  pages. 

*  Bulletin  186,  U.  S.  Department  of  Agriculture,  1915. 


SUMMARY.  2  1 

Most  of  these  insects  may  be  destroyed  by  raising  the 
temperature  to  a  point  between  1200  and  1300  F.  for  five  or  six 
hours.  The  vitality  of  seeds  is  endangered  if  the  heat 
approaches  1500  F.  but  the  material  would  not  be  injured  for 
food. 

Food  kept  in  cold  storage  will  not  be  injured  by  insects. 

Various  pest  proof  packages  have  been  devised,  but  food 
often  becomes  infested  in  them,  and  no  package  is  pest  proof 
after  the  seal  has  been  broken. 

Air-slaked  lime  applied  to  seeds  when  placed  in  storage 
will  prevent  most  of  the  damage  caused  by  the  pea  and  bean 
weevils.  The  proportions  are  as  follows:  For  small  quanti- 
ties, say  less  than  a  half  peck,  four  parts  of  lime  to  one  part 
of  seeds ;  between  a  half  peck  and  three  bushels,  equal  parts 
of  lime  and  seeds ;  for  greater  quantities,  one  part  of  lime  to 
two  parts  of  seed. 

Fumigating  with  carbon  disulphide,  using  a  half  cupful  to 
a  barrel,  will  rid  the  material  of  insect  life,  This  liquid 
should  be  placed  on  top  of  the  infested  material,  and  should 
not  be  used  near  a  fire  as  it  is  inflammable.  The  container 
should  be  tightly  covered  for  twenty-four  hours  or  longer. 

Hydrocyanic  acid  gas  may  also  be  used  but  is  not  advised 
except  in  particular  cases,  as  it  is  deadly  to  breathe  and  does 
not  penetrate  masses  of  flour  and  grain  readily.  Seeds  and 
food  materials  if  thoroughly  aired  are  not  injured  by  carbon 
disulphide  or  hydrocyanic  acid  gas,  either  for  food  or  for 
planting. 

For  more  detailed  information  on  this  subject  the  reader 
should  refer  to  the  pages  of  this  bulletin. 


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